Fluid flow and leak detection systems for plumbing systems provide a valuable function by protecting the surrounding environment (indoor or outdoor) from damage due to fluid leakage. Such damage can far exceed the cost of the leaked fluid, and the combined annual cost of building damage from leaking plumbing systems exceeds $1 B in the United States. Leaks in outdoor plumbing systems are also a pervasive problem, with industry analysts estimating that 30% of treated potable water is lost to leaks.
Despite the pervasive nature and high consequential cost of plumbing leaks, products capable of detecting leaks that have been on the market for many years have seen limited market penetration.
Systems designed for identifying leaks in indoor plumbing systems are currently either too costly, too difficult to install or provide limited protection. The dominant approach for such systems relies on moisture sensors that are activated by contact with pooling water under or near the leak.
It is common to see apparatuses that either employ a float-switch or an electronic moisture sensor as the detection apparatus. These apparatuses, an example given by the Leak Alert water detector by Zircon, resemble a puck or small box which is placed in an area where fluid pooling is expected upon the failure of a local pipe system. An example would be at the lowest point of the floor under the water circuit of an air conditioning system. Another example of this category employs the use of Time Domain Reflectometry (TDR) or impedance changes to detect moisture contacting a wire or mesh of wires. These apparatuses, an example being the ProH2O system by Safe Fire Detection, Inc, have a small sensing unit connected to a length of detection cable or wire, which is strung in an area expected to become wet upon the failure of a local pipe system.
Using apparatuses of this category requires precise knowledge of where leaked fluid will flow and requires a sufficient volume—sometimes significant—of leaked fluid to pool at the apparatus in order for a leak to be detected. Additionally, because they detect fluid only locally, a large number of such apparatuses are needed for adequate surveillance of a significant pipe network, for example that found in a residence or commercial building.
Leaks in outdoor plumbing systems are generally detected using highly trained professionals with sophisticated and costly portable acoustic monitoring equipment. These units are affixed to elements in the plumbing network such as fire hydrants, and the equipment picks up sounds that trained personnel can recognize as originating from underground leaks. While proven effective, this labor-intensive approach proves too costly for continuous or widespread use. Furthermore, the specialized nature of the identification limits the scalability of this approach.
Another approach to leak detection utilizes highly accurate flow meters that enable system operators to identify leaks through mass-balance calculations. Sensors used in these systems require high accuracy, and as a result are focused only on the flow conditions in the pipe to which they are attached. Additionally, their high accuracy usually comes with moderate to high power requirements, high cost and sometimes difficulty of installation. The high power requirement can be especially problematic because it either precludes battery operation, or the product has a short lifetime between battery replacements.